JP2910245B2 - Driverless vehicle safety devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for an unmanned vehicle that transports goods between a plurality of stations provided at predetermined locations.

[0002]

2. Description of the Related Art Unmanned vehicles such as unmanned forklifts are used to transport luggage stored at a predetermined position in a warehouse, factory, or outdoors to another storage location or a temporary loading position. Generally, an unmanned vehicle travels along a guide line laid between a plurality of luggage storage locations (stations). As shown in FIG. 7, an unmanned vehicle (unmanned forklift) 30 is equipped with an ultrasonic sensor 31 for detecting an obstacle ahead in the traveling direction. When the ultrasonic sensor 31 detects an obstacle during traveling, a detection signal is output. , The traveling of the unmanned vehicle 30 is stopped. However, when the ultrasonic sensor 31 operates when the unmanned forklift 30 approaches the station S and performs the cargo handling operation, the station S entering the detection area of the ultrasonic sensor 31 (indicated by a dashed line in FIG. 7) becomes an obstacle. It is judged that unmanned forklift 3
Since the running of the vehicle is stopped, the work cannot be performed. Therefore, conventionally, when the unmanned forklift 30 approaches the station S and performs the cargo handling operation, the obstacle detection function of the ultrasonic sensor 31 is disabled and the cargo handling operation is performed. Note that the arrival of the unmanned forklift 30 at the station S means that a mark plate sensor (not shown) provided on the unmanned forklift 30 detects a mark plate disposed at a predetermined position along the guide line. Is to be confirmed by.

[0003] In addition to an ultrasonic sensor, a bumper-type sensor is also provided. When an unmanned vehicle travels between stations, an obstacle is detected by the ultrasonic sensor, and the detection function of the ultrasonic sensor is disabled. There is also proposed an unmanned vehicle in which an obstacle is detected by a bumper-type sensor when the vehicle travels in a state where the vehicle travels in an unsteady state (Japanese Patent Laid-Open Publication No. Hei 2-235113). Or,
Japanese Utility Model Publication No. Hei 2-40001 discloses a device for preventing interference between a stacker crane and a transport trolley in an automatic warehouse, which emits a light beam in the direction of entry of the transport trolley into and out of the loading / unloading station and forks of the stacker crane at the loading / unloading station. A light emitter is provided at a position where the fork blocks the light beam in a state in which the light enters, a light receiver is provided at a position where the light beam can be received on the transport vehicle, and the light receiver is placed in a state where the transport vehicle approaches the entrance / exit station. There is disclosed an apparatus provided with a determination unit for prohibiting entry of a transport trolley when a light beam cannot be received.

[0004]

In the above-mentioned conventional apparatus, the detection function of the ultrasonic sensor 31 is disabled when approaching the station and during unloading work, so that the unmanned forklift 30 detects an obstacle in front. And may come into contact with obstacles. On the other hand, even in an unmanned vehicle equipped with a bumper-type sensor in addition to the ultrasonic sensor, detection cannot be performed depending on the position of the obstacle (for example, the left and right guide rails that guide the mast carriage of a reach-type forklift). If there is). Also, in order not to give an impact when the bumper comes into contact with an obstacle, the unmanned vehicle must run at a very low speed,
When applied to an unmanned forklift, there is also a problem that work efficiency is reduced.

In the apparatus disclosed in Japanese Utility Model Publication No. 2-40001, the interference between the transport trolley and the stacker crane at the loading / unloading station can be prevented. However, the detection of obstacles while the transport trolley moves to another station is described. Nothing is considered. In order to use the light receiver provided on the transport vehicle (unmanned vehicle) for detecting an obstacle on the travel route of the transport vehicle, there is a problem that a large number of light emitters are required on the travel route of the transport vehicle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object the purpose of connecting between an unmanned vehicle and a station when traveling between stations, approaching the station, and loading / unloading work. An object of the present invention is to provide a safety device for an unmanned vehicle that can reliably detect an obstacle that is present therebetween.

[0007]

In order to achieve the above object, according to the present invention, there is provided an unmanned vehicle for carrying a load between a plurality of stations provided at a predetermined location, the unmanned vehicle being equipped with the unmanned vehicle and being provided in front of the traveling direction. A first sensor (for example, an ultrasonic sensor) for detecting the presence or absence of an obstacle by using a reflected wave from the obstacle, and a plurality of sensors are provided on the traveling direction side of the unmanned vehicle when the unmanned vehicle approaches each of the stations. A second sensor of photoelectric type (projection / reception type or light reception type), a light transmitting member provided at a predetermined position of each station facing the unmanned vehicle and transmitting light toward the second sensor, and an unmanned vehicle. The station
When traveling between vehicles, obstacles are detected by the first sensor.
The unmanned vehicle moves a predetermined distance
When it is located within the distance, the second sensor
Switching means for switching the operation timing of the first sensor and the second sensor in a state of detecting an object is provided.

[0008]

[Function] When an unmanned vehicle moves between stations ,
The first sensor is kept in a state of detecting an obstacle, and if there is an obstacle on the traveling path of the unmanned vehicle, the first sensor detects it. Unmanned vehicles are at a certain distance from the station
When the vehicle is located within a distance, for example, when an unmanned vehicle approaches the station and loads and unloads the cargo, the operation of the switching means causes the second sensor to detect an obstacle, and the second sensor detects an obstacle. The presence of an obstacle between the unmanned vehicle and the station is detected by the sensor . The second sensor irradiates itself and receives light reflected by a light transmitting member provided in the station or light irradiated from the light transmitting member. Light is blocked if the obstruction between the unmanned vehicle and a station is present, the presence of the obstacle Ru is detected by the second sensor.

[0009]

(Embodiment 1) A first embodiment in which the present invention is embodied in a reach type unmanned forklift will be described below with reference to FIGS. As shown in FIG. 3, luggage storage location 1 as a station
A guide line 3 through which a guide signal flows is laid between the vehicle and the loading / unloading table 2, and a traveling path of the unmanned forklift 4 is set. The unmanned forklift 4 moves along the traveling path by detecting the guide wire 3 with a pair of left and right traveling pickup coils (not shown) mounted on the rear side (the side opposite to the side where the fork 5 is mounted). It has become.
Mark plates 6 and 7 are fixedly arranged at predetermined positions in front of the storage place 1 and the loading / unloading table 2, and another mark plate 8 is fixedly arranged at a predetermined position apart from the mark plates 6 and 7 along the traveling path. ing. Each mark plate 6-8
Are arranged in two rows in a direction perpendicular to the guide wire 3 (however, the number of mark plates or the combination of arrangements is different).

As shown in FIGS. 1 and 2, above the front wheels 10 on the front side of the unmanned forklift 4 (the side on which the fork 5 and the mast 9 are mounted), the presence or absence of an obstacle is determined by using the reflected wave from the obstacle. A pair of ultrasonic sensors 11 as a first sensor for detecting the position of the unmanned forklift 4 is provided, and one ultrasonic sensor 12 is provided at the rear center of the unmanned forklift 4.
In front of the unmanned forklift 4, a plurality of (five in this embodiment) photoelectric sensors 13 of light emitting and receiving type as second sensors are provided at equal intervals in the width direction of the unmanned forklift 4. Two of the five photoelectric sensors 13 are disposed outside the ultrasonic sensor 11, and three are support bars installed inside the distal end of a guide rail 14 for guiding a mast carriage (not shown). 15.
When the unmanned forklift 4 moves forward, the storage location 1 and the loading / unloading table 2 facing the unmanned forklift 4 serve as a light transmitting member for transmitting light toward the photoelectric sensor 13 at a position facing each of the photoelectric sensors 13. The reflection plates 16 are fixed respectively. The detection ranges of the ultrasonic sensors 11 and 12 are divided into two stages as shown in FIGS. 4 and 5, the detection range of the first area A1 is within approximately 2 m, and the detection range of the second area A2. Is within approximately 1 m. On the other hand, each of the photoelectric sensors 13 has a distance of approximately 1 m from the reflection plate 16 and the second
In a range slightly larger than the area A2 of the photoelectric sensor 13
, And a predetermined amount of light reflected by the reflection plate 16 can be reliably received. In addition, fork 5
The minimum height of the ascending / descending range is such that the fork does not interfere with the photoelectric sensor 13 disposed on the support bar 15 when the fork is disposed at that position.

As shown in FIGS. 1 and 2, two sets of mark plate detection sensors 17 for detecting the mark plates 6 to 8 are provided at the bottom of the unmanned forklift 4. At the rear of the unmanned forklift 4, a microcomputer 18, a travel controller 19, and a travel pulse output device 20 are installed. The travel controller 19 controls the drive of a travel motor (not shown) for driving the drive wheels 21 based on a command from the microcomputer 18.

The microcomputer 18 includes a central processing unit (CPU) 22 as switching means for switching the operation timing of the ultrasonic sensor 11 and the photoelectric sensor 13, an interface 23, and a program memory 24 comprising a read-only memory (ROM). And a working memory 25 comprising a readable and rewritable memory (RAM). The CPU 22 operates based on a control program stored in the program memory 24. In the program memory 24, data of operation instruction contents for the arrangement patterns of the mark plates 6 to 8 is stored in advance. Further, detection signals from the ultrasonic sensors 11 and 12, the photoelectric sensor 13 and the mark plate detection sensor 17 and an output signal from the traveling pulse output device 20 are input to the CPU 22 through the interface 23. ing. And the CPU 22
When it is determined from the detection signals of the ultrasonic sensors 11 and 12 that an obstacle exists in the first area A1, the traveling controller 19 controls the unmanned forklift 4 at a predetermined low speed .
It sends a command signal to run the line. Also, the second area A
When it is determined that an obstacle exists in the traveling controller 2, a stop command signal is sent to the traveling controller 19.

Next, the operation of the device configured as described above will be described. The unmanned forklift 4 moves backward during normal running, that is, with the side opposite to the fork 5 forward. In this state, the ultrasonic sensor 12 provided on the rear side of the unmanned forklift 4 is kept in the operating state, and an obstacle on the traveling road is detected. When the unmanned forklift 4 continues traveling along the traveling path toward the loading / unloading table 2 and the mark plate detection sensor 17 detects the mark plate 8,
The traveling controller 19 stops the traveling motor, and the unmanned forklift 4 stops traveling. Next, the traveling controller 19 controls the driving of the traveling motor so as to perform the spin turn, and the unmanned forklift 4 performs the spin turn to change the direction by 180 °. At this time, the operation of the ultrasonic sensor 12 disposed on the rear side is stopped, and the ultrasonic sensor 11 and the photoelectric sensor 13 disposed on the front side are maintained in the operating state. After the spin turn, unmanned forklift 4
Moves with the fork 5 in front. When the mark plate detection sensor 17 detects the mark plate 6, C
The PU 22 starts counting the output signal of the traveling pulse output device 20 from that point and calculates the moving distance from that point. Then, a command signal for controlling the driving of the traveling motor is output to the traveling controller 19 so that the unmanned forklift 4 stops at the luggage transfer position at a predetermined distance from the position.

The installation position of the mark plate 6 and the loading / unloading table 2
Is greater than the distance at which the photoelectric sensor 13 can receive a predetermined amount of reflected light from the reflector 16. Therefore, the distance between the loading / unloading table 2 and the unmanned forklift 4 is determined by the photoelectric sensor 1.
Until the effective range becomes 3, the presence or absence of an obstacle is detected by the ultrasonic sensor 11. When the loading / unloading table 2 enters the first area A1 of the ultrasonic sensor 11, the traveling speed of the unmanned forklift 4 is changed to a predetermined low speed. From this state, the unmanned forklift 4 continues to advance, and the unmanned forklift 4 reaches a position where all the photoelectric sensors 13 can receive a predetermined amount of reflected light from the reflecting plate 16. After receiving the reflected light from
The CPU 22 switches to a state where the detection signal of the ultrasonic sensor 11 is invalidated based on the detection signal from the photoelectric sensor 13. The time when the detection signal of the ultrasonic sensor 11 is invalidated is not limited to the time immediately after all the photoelectric sensors 13 receive the reflected light from the reflecting plate 16, and may be after the state is continued for a predetermined time. After that, the photoelectric sensor 13 detects the presence or absence of an obstacle between the unmanned forklift 4 and the loading / unloading table 2.

If there is an obstacle between the unmanned forklift 4 and the loading / unloading table 2, one or more photoelectric sensors 13 cannot receive the reflected light from the reflecting plate 16. CPU2
2 outputs a stop command signal to the traveling controller 19 when the light receiving signal from at least one photoelectric sensor 13 stops, and the unmanned forklift 4 stops. After that, the obstacle is removed and the reflection plate 16 is
When the reflected light from the vehicle is received, the CPU 22 outputs a traveling command signal to the traveling controller 19, and the unmanned forklift 4 starts traveling again.

The traveling controller 19 outputs a stop command to the traveling motor when the unmanned forklift 4 has moved a predetermined distance from the position corresponding to the mark plate 6, and the traveling motor is stopped and the brake is applied, so that the unmanned forklift 4 is operated. The cargo is stopped at a proper stop position for the transfer of the load, and the transfer of the load is performed. As described above, the unmanned forklift 4 is provided with the ultrasonic sensors 11 and 12 and the photoelectric sensor 13, and the photoelectric sensor 13 is used for detecting an obstacle at a position close to the loading / unloading table 2. The ultrasonic sensors 11 and 12 are used for detecting an obstacle at the time.
Therefore, unlike the conventional device, there is no obstacle undetectable band at a position close to the loading / unloading table 2, and the occurrence of contact with the obstacle during the transfer (unloading) of the load is prevented beforehand. .

Embodiment 2 Next, a second embodiment will be described with reference to FIG. This embodiment is different from the first embodiment in that the ultrasonic sensor 11 is disabled and the photoelectric sensor 13 detects an obstacle so that the operation timing of the two sensors is switched. In this embodiment, the mark plate 26 is located at a position corresponding to the mark plate detection sensor 17 when the unmanned forklift 4 reaches a position where all the photoelectric sensors 13 can receive a predetermined amount of reflected light from the reflector 16.
Are fixedly arranged. Further, when the unmanned forklift 4 is at a position corresponding to the mark plate 26, a second area A2 is set so that the loading / unloading table 2 does not enter the second area A2 of the ultrasonic sensor 11. At the time when the unmanned forklift 4 starts to move forward toward the loading / unloading table 2, only the ultrasonic sensor 11 is kept in the operating state. Until the unmanned forklift 4 reaches a position corresponding to the mark plate 26, the ultrasonic sensor 11 detects an obstacle. Mark plate detection sensor 1
When 7 detects the mark plate 26, the CPU 22 disables the detection function of the ultrasonic sensor 11 and switches the photoelectric sensor 13 to the operating state based on the detection signal. After that, an obstacle is detected by the photoelectric sensor 13.

The present invention is not limited to the above-mentioned two embodiments. For example, the photoelectric sensor 13 and the reflector 1
Change the number of 6 or enter and exit as a station 2
Alternatively, the reflection plate 16 is provided on the storage location 1 side with the photoelectric sensor 13.
A single horizontally long reflecting plate is provided instead of a plurality of light reflecting members, or a light receiving photoelectric sensor is used as a second sensor instead of the photoelectric sensor 13, and a light transmitting member is provided on the station side. A light projector may be provided instead of the reflection plate 16. The detection range of the ultrasonic sensor 11 is 2
Instead of being divided into stages, one stage may be adopted. In that case, the detection range of the ultrasonic sensor is set narrower than the detection range of the photoelectric sensor 13. Furthermore, the present invention is not limited to the unmanned forklift 4 and may be applied to an unmanned transport vehicle that only transports luggage.

[0019]

As described above in detail, according to the present invention, when an unmanned vehicle travels between stations, the first sensor detects the presence of the unmanned vehicle when approaching the station and during the unloading operation of the load. The two sensors can reliably detect an obstacle present in front of the unmanned vehicle, and unlike the conventional device, there is no area where the obstacle detection sensor does not function, and the contact with the obstacle is prevented beforehand. Therefore, safety is ensured not only at the time of traveling of the unmanned vehicle but also at the time of cargo handling.

[Brief description of the drawings]

FIG. 1 is a schematic side view of an unmanned forklift according to a first embodiment.

FIG. 2 is a schematic plan view showing an arrangement relationship of a reflection plate, a light emitting / receiving sensor, an ultrasonic sensor, and the like.

FIG. 3 is a schematic plan view showing an arrangement relationship between a traveling path of an unmanned forklift and stations.

FIG. 4 is a schematic plan view showing the operation.

FIG. 5 is a schematic side view showing the operation.

FIG. 6 is a schematic side view showing the operation of the second embodiment.

FIG. 7 is a schematic side view of a conventional unmanned forklift.

[Explanation of symbols]

 Reference Signs List 1 Storage location as a station 2 Loading / unloading table as a station 4 Unmanned forklift as an unmanned vehicle 11 Ultrasonic sensor as a first sensor 13 Photoelectric sensor as a second sensor 16 Reflector plate as a light transmitting member 22 Switching CPU as a means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G05D 1/02 B66F 9/24

Claims (1)

(57) [Claims] 1. An unmanned vehicle for carrying luggage between a plurality of stations provided at a predetermined location, the presence or absence of an obstacle in the traveling direction of the unmanned vehicle using a reflected wave from the obstacle. A first sensor for detecting, a plurality of photoelectric sensors provided on a traveling direction side of the unmanned vehicle when the unmanned vehicle approaches each of the stations, and a predetermined position of each station facing the unmanned vehicle. a light-sending member for sending the light toward the second sensor is provided, the unmanned vehicle is the stay
When traveling between stations, the first sensor causes an obstacle.
When an unmanned vehicle is in contact with the station,
When located within a fixed distance, the second sensor
A safety device for an unmanned vehicle, comprising: switching means for switching the operation timing of the first sensor and the second sensor in a state of detecting an obstacle .